Large fluorescence enhancement of a hemicyanine by supramolecular interaction with cucurbit[6]uril and its application as resettable logic gates

About 270 times fluorescence enhancement was observed when the hemicyanine dye, trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DSMI), was included by cucurbit[6]uril (CB[6]). The 1:1 stoichiometry of DSMI/CB[6] complex was determined through optical spectra and 1H NMR measurement. The large fluorescence enhancement was achieved by prohibiting the twisted intramolecular charge transfer (TICT) process of DSMI inside the distorted cavity of CB[6], together with the ion-dipole interaction between DSMI and CB[6]. The distortion of the CB[6] cavity, being as the major reason for the great fluorescence enhancement, was further confirmed in the calculation results. A resettable and reconfigurable logic gate was also constructed with DSMI and CB[6] under different pH situations. This study lays a solid foundation for the design of molecular logic gates by a supramolecular interaction mode.

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► Suparmolecular interaction bewteen hemicyanine DSMI and cucurbit[6]uril was studied.
► About 270 times fluorescence enhancement can be achieved for the system.
► A resettable and reconfigurable logic gate was constructed with DSMI and CB[6].